1. Field of the Invention
The invention is related to a ski boot, and more specifically to a device for adjusting the advance or forward movement of the upper thereof. The present invention is especially related to an alpine ski boot that includes a rigid shell base adapted to surround the foot and an upper overlying the shell base, adapted to surround and envelop the lower part of the leg of a skier and, at the same time, enabling him or her to flex the leg at least partially forwardly when subject to thrusts originating during skiing.
This ski boot that can be of the central-entry type, that is, by simultaneous separation towards the front and towards the rear of two portions of the upper, or of the rear-entry type having, as per the invention, a device for adjusting the angle of advance of the upper with respect to the shell base of the boot in the position of use.
2. Description of Background and Material Information
Currently, there are alpine ski boots on the market that comprise such adjustment devices adapted to ensure, with the required technicity, the transmission of forces applied by the leg of the skier in the area of the upper, in accordance with the ski technique practiced, with the morphology of the skier, and even with the type of terrain. Indeed, to enable skiers to use such boots in different alpine ski disciplines, such as competitive skiing, skiing outside the run, etc., it is desirable, and sometimes even necessary, to be able to vary the angle of front inclination or the angle of advance of these boots.
Such boots have been described in French Patent Publication Nos. 2,024,700 and 2,276,850, for example. However, although these boots enable a variation in the angle of advance, in the majority of cases they are uncomfortable insofar as tibial support for the leg of the skier is concerned during front flexion exercised during skiing. This discomfort is provoked by the constructional arrangement of the devices used, and is reinforced by the fact that its manipulation is awkward, especially when the skier has the boot on, and is obliged to undo it and modify all the closure and tightening adjustments.
Thus, the boot according to French Patent Publication No. 2,024,700 comprises an adjustment device that enables a modification of the angle of advance to be obtained by modifying the grip position, on the upper front portion of a rigid shell base, of the relatively flexible wings of a rear spoiler journalled on such shell base. With this boot, front flexion is permitted basically at an area of a front tongue mounted at a journal on the shell base, and control of this flexion can only be obtained by the cooperation of the flexible wings, by friction and lateral separation, the tongue being in support against such wings. In this specific case, the adjustment of the angle of advance of the upper only produces really substantial effects when there is rear support of the leg because the flexible wings open during forward separation.
As regards the ski boot according to French Patent Publication No. 2,276,850, the adjustment of the advance is obtained by modifying the length of the perimeter of the front enveloping of the lower part of the leg by the upper. This upper in fact originates from the shell base that rises towards the tibial support zone by forming a front portion provided with a median slot that ends in a hole. This front portion of the shell-upper is covered by a strap journalled laterally on the shell that extends towards the rear to ensure, by means of hooks, the closure of the upper. The adjustment of the angle of advance is thus obtained by insertion of a wedge, shaped like an inverted key hole, in the slot and the hole whose edges it separates, such that the periphery of the upper is modified. After such modification, by the tightening of the strap on the upper, which is displaced according to the value of the size of the wedge, the angle of advance of such upper is also modified. In this example, it is thus necessary to have available several wedges having different sizes to obtain a progressive variation of the angle of advance. Additionally, the positioning of this wedge beneath the covering strap is awkward because the material of the upper shell is relatively rigid and can only be separated with difficulty.